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PubMed2026

A rare and atypical case of long-distance indirect DNA transfer: Contamination from an investigator never present at the scene.

To maximize the usefulness of DNA obtained from biological samples in forensic genetics, it is crucial to avoid DNA contamination throughout all procedures, from sample collection at crime scenes to STR profile generation in DNA laboratories. This study reports a rare and atypical case of DNA contamination in a forensic setting. During the analysis of biological evidence from a cold case preserved for 18 years, the STR profile obtained from the surface of a plastic bag matched that of an investigator, identified through the DNA elimination database. Case reconstruction confirmed that the investigator-who was located 80 km from the DNA laboratory and had never entered the crime scene or the sample storage room-was not a suspect and that the obtained STR profile originated from contamination. The most plausible explanation for the contamination was indirect transfer: investigator's DNA had adhered to a colleague's clothing and was subsequently dislodged and deposited onto the surface of the plastic bag as the colleague approached the sample pretreatment area. This study integrates trace DNA profiling of challenged samples with rapid contamination investigation and proposes prevention and control measures. This case underscores that, although DNA is widely regarded as the "gold standard" in forensic genetics, its interpretation must be considered within the context of the entire case. Conclusions should not be drawn based solely on a single DNA result.

Humans↗
PubMed1994

HUMTH01: amplification, species specificity, population genetics and forensic applications.

Length variation at the short tandem repeat (STR) locus HUMTH01 can be reliably detected from small amounts of DNA (0.01-10 ng) extracted from a range of forensic human samples, using the polymerase chain reaction (PCR), horizontal polyacrylamide gels and silver staining. It was shown that the oligonucleotide primers used are specific to humans and some higher primates. Population data bases of Caucasians and Asians living in Victoria (Australia) were constructed and the differences in allele frequencies between Caucasians and Asians confirmed. A new allele provisionally designated HUMTH01*12 was identified. The discrimination power provided by this locus (0.86-0.91) has been used effectively in a range of forensic case studies.

Alleles↗
PubMed2026

pSTRminer: integrated bioinformatic software for genome-wide identification and population-scale evaluation of polymorphic short tandem repeats.

Animal forensic genetics plays a critical role in criminal investigations by providing crucial evidence through domestic animal individualization and wildlife species identification. While human forensic genetics benefits from standardized short tandem repeats (STR) genotyping systems, animal forensic applications encounter significant challenges, including the limited availability of validated STR markers, the prevalence of error-prone dinucleotide STRs (di-STRs), and insufficient integration of population data. To address these challenges, we developed pSTRminer, an integrated bioinformatic tool that automates genome-wide STR mining and polymorphism evaluation. By applying pSTRminer to domestic cattle (Bos taurus), we identified 775,444 STRs de novo from the reference genome and genotyped them using whole-genome sequencing data from 60 Chinese and 111 African cattle to evaluate polymorphism across diverse genetic backgrounds. This led to the development of the cattle STR database (CSDB), comprising loci with a genotyping success rate&#x2009;&#x2265;&#x2009;40% and polymorphism information content (PIC)&#x2009;&#x2265;&#x2009;0.5. Experimental validation of 30 randomly selected tetranucleotide STRs (tetra-STRs) and 33 di-STRs via next-generation sequencing in a local Chinese cattle population (n&#x2009;=&#x2009;145) confirmed marker reliability. Although tetra-STRs had lower average polymorphism levels, they exhibited significantly lower stutter ratios (p&#x2009;<&#x2009;0.05), providing a viable path for identifying discriminative markers with fewer artifacts. Systematic screening revealed that certain tetra-STRs could surpass di-STRs in polymorphism. In conclusion, pSTRminer provides a scalable framework for developing standardized STR panels, facilitating the identification of robust and informative markers in forensic applications.

Bioinformatic software↗
PubMed2006

Application of plant DNA markers in forensic botany: genetic comparison of Quercus evidence leaves to crime scene trees using microsatellites.

As highly polymorphic DNA markers become increasingly available for a wide range of plant and animal species, there will be increasing opportunities for applications to forensic investigations. To date, however, relatively few studies have reported using DNA profiles of non-human species to place suspects at or near crime scenes. Here we describe an investigation of a double homicide of a female and her near-term fetus. Leaf material taken from a suspect's vehicle was identified to be that of sand live oak, Quercus geminata, the same tree species that occurred near a shallow grave where the victims were found. Quercus-specific DNA microsatellites were used to genotype both dried and fresh material from trees located near the burial site and from the material taken from the suspect's car. Samples from the local population of Q. geminata were also collected and genotyped in order to demonstrate that genetic variation at four microsatellite loci was sufficient to assign leaves to an individual tree with high statistical certainty. The cumulative average probability of identity for these four loci was 2.06x10(-6). DNA was successfully obtained from the dried leaf material although PCR amplification was more difficult than amplification of DNA from fresh leaves. The DNA profiles of the dried leaves from the suspect's car did not match those of the trees near the crime scene. Although this investigation did not provide evidence that could be used against the suspect, it does demonstrate the potential for plant microsatellite markers providing physical evidence that links plant materials to live plants at or near crime scenes.

DNA, Plant↗
PubMed1998

Population genetics and forensic applications using multiplex PCR (CSF1PO, TPOX, and TH01) loci in the Basque Country.

A population study in a sample of 200 unrelated individuals from the Basque Country (Northern Spain) was carried out using the GenePrint STR Multiplex System. The PCR products were electrophorized on a denaturing polyacrylamide gel and visualized by silver staining. The loci are TH01, TPOX, and CSF1PO. All loci meet Hardy-Weinberg expectations, and independence of alelles at these STR loci was found. A comparison with other population groups appeared to indicate that frequencies are well conserved in Caucasians, but differ from those of other racial groups. We have also calculated Fst as a measure of population subdivision. No appreciable genetic subdivision in the Caucasian populations studied here was found. Some statistical parameters of forensic interest (Pex, PM and PD) were also calculated. No exclusions were found in 100 mother-child and father-child meiosis. To evaluate the applicability of these systems to forensic casework, we studied the minimum quantity of DNA which can be used applying the multiplex methodology, and the minimum quantity that can be typed in a mixed sample. We also examined several samples such as hair roots, semen stains, vaginal swabs, blood stains and temporary teeth, each of these of varying ages.

Alleles↗
PubMed2002

Yfm1, a multicopy marker specific for the Y chromosome and beneficial for forensic, population, genetic, and spermatogenesis-related studies.

A recently developed microsatellite marker on the Y chromosome, Yfm1, which was originally cloned from a cosmid clone mapped near the DAZ (Deleted in AZoospermia) genes, was used to classify Y chromosomes using an automatic sequencer. Yfm1 could detect multicopies on Y chromosomes in a single polymerase chain reaction, showing four main classes, A, A*, B, and C, according to the number of copies and peak patterns. Compound haplotype analysis of the Y chromosome using the Yfm1 marker with three other biallelic markers on the Y chromosome, SRY, DXYS5Y, and YAP, resulted in nine different haplotypes among different populations, including Japanese. Haplotype II (defined by YAP insertion) observed in the Japanese population was consistently associated with Yfm1 class A or A*, which showed the lowest number of copies of Yfm1. Haplotypes III and IV were consistently associated with Yfm1 class B. On the other hand, haplotype I showed a variety of Yfm1 patterns that were dubbed class C when not appropriately classified as A, A*, or B. These relationships among Yfm1 microsatellite and Y-specific biallelic markers could supply useful population genetic information. Moreover, because we have already shown that men with haplotype II have significantly lower spermatogenic ability than those with other haplotypes, Yfm1 class A or A* with the least number of copies may be related to the haplotype II-specific structure of the Y chromosome, such as deletion of DAZ or DAZ repeats, reflecting the lower spermatogenic abilities of Japanese haplotype II men. Thus, Yfm1 represents a very useful marker for analysis of genetic structure in different populations and studies on Y chromosome lineage-specific genotype-phenotype correlations.

Alleles↗
PubMedDate not supplied

[Utilization of complex technologies of molecular genetics for forensic expert identification of unidentified remains of victims of terrorist acts in Moscow in 1999].

This paper presents the first experience gained in Russia in expert identification practice with complex utilization of technologies of molecular genetic individualization of biological objects for solving identification tasks requiring the maximum complete armory of mutually supplementing means. This is particularly important for forensic expert personality identification in cases with many deaths, when indirect identification has to be resorted to, consisting in the use of biological samples from relatives of the victims as the identifying objects. Methodological approaches and concepts of expert studies, used for identification of the remains of people who died in terroristic acts committed in Moscow in September, 1999, are discussed. The results of this study and methodological experience notably extend the potentialities of expert evaluation as regards forensic medical identification of victims of overall disasters, terroristic acts, and war conflicts.

Cadaver↗
PubMed1995

[Searching for genetic markers--in the fields of forensic medicine and human genetics].

Research on genetic markers in the fields of forensic medicine and human genetics did not begin in earnest until 1968. Study of an extended family in Wakayama Prefecture resulted in the discovery of the variant Bm type in the ABO blood group system. This family of nearly 40 members composed of Group A, B, O and AB spouses and type Bm monozygotic twins provided the best research material possible. An extremely rare case of an individual with type O red blood cells but no anti-A or anti-B antibodies led to the discovery of type AmBm. Fishman and Mitsuhashi advocated the concept of immunogenetic RNA. We attempted to examine the immunogenetic RNA function by isolating RNA from the human spleen but obtained no definitive results. Many researchers had since examined the genetic markers in erythrocytes, leukocytes, serum proteins and blood cell enzymes, but research on genetic marker in saliva had not been advanced. We searched for genetic markers in the parotid saliva and developed the PmF and Ph systems. A salivary amylase variant and acid phosphatase polymorphism were also discovered. We elucidated the genetic structure and geographic gradinet of the salivary genetic markers, such as the Pa, Pb, Pr, Db and PIF systems, in Japanese. The genetic markers in the tear and saliva of mice and rats were also detected. We demonstrated RFLP polymorphism using an amylase cDNA probe. Our report was one of the first on polymorphism in the field of forensic medicine in Japan. Interest was also directed to polymorphism in platelet and we employed two-dimensional electrophoresis to establish the ThA and ThB systems which are controlled by autosomal codominant genes. Regarding the research on monoclonal antibody production and their application in forensic medicine, we cloned and produced antibodies for ABO, MN and Lewis grouping. Anti-glycopholin-A, anti-glycopholin-B and anti-glycolipid monoclonal antibodies were also produced and used to divide the red blood cell antigens roughly into three classes; the glycopholin-A (MN), glycopholin-B (Ss. Duffy Kell-Cellano, Lutheran, Diego, Xg) and the glycolipid (ABO, Lewis, P) classes. Red blood cell protein membrane proteases were also isolated from Nepenthes alata extract and lectin which are used in grouping animal blood cells. In the research on erythrocyte differentiation and erythrocyte group substance expression, we established a selective two phase liquid culture system for culturing precursor cells of peripheral erythrocytes, and demonstrated the expression of red blood cell antigens such as ABO, Rh and Duffy antigens in the early period (4 to 9 days) of Phase 2. Recently, research on identifying the genes which code for polymorphism in erythrocytes or erythrocyte enzymes is making progress. For example, a study indicated a possible relationship between an isoform of the glycophorin A gene and the MN variant. In the cDNA sequence of the Fy (a-b+) and (a + b-) types in the Duffy system, a GAT (Asp) to GGT (Gly) substitution in the codon for residual 44 was detected. Research on the Rh gene is being pursued energetically. Two clones of the Rh gene have been isolated; Rh Pl composed of 1251 bases, and Rh Pll estimated to be Ph PI with a base substitution at position 41 and an amino acid substitution at position 31. Seven isoforms of Ph Pl and 5 isoforms of Ph Pll have been obtained. The delineation of the Rh gene which contains as many as 50 types of Rh antigen genes is in progress. The red blood cell enzyme EsD system is also used commonly in the field of forensic genetics. In EsD polymorphism, type EsD1 contains G at base 569, type EsD2 contains A and type EsD1-2 shows a heterologous conjugation of G and A. Due to the development of immunosuppressive agents, bone marrow transplant can now be conducted even when the ABO and Rh systems are not compatible, as long as the HLA is compatible. In this case, all the erythrocyte polymorphic types or erythrocyte enzyme polymorphic types are transformed to t

ABO Blood-Group System↗
PubMed1988

Factor B (BF) subtyping by isoelectric focusing: methods, nomenclatures, genetics and forensic application.

Usually factor B (BF) typing is performed by means of the traditional agarose gel electrophoresis. Using isoelectric focusing, the system can be extended by two common subtypes of BF F. The existence of BF F subtypes has in the meantime been confirmed by various authors and in different populations. Their inheritance has been proven by family- and mother/child analyses and molecular-genetic studies (correlation with restriction fragment length polymorphism). Different typing methods as well as different nomenclatures seem to indicate that the subtypes FA and FB (according to Geserick et al.) are identical with the Fb and Fa subtypes (according to Teng and Tan). At present, some confusion still exists for the less frequent variants and subtypes which possibly could be identified by direct comparison of the patterns. The BF system is a valuable marker in paternity testing. Its chance for exclusion of paternity in Caucasian populations has been calculated to be about 14% for agarose gel electrophoresis and increases to about 16% for BF F subtyping by isoelectric focusing. Preliminary results indicate that BF may also be used for typing of bloodstains (up to 2 weeks old).

Complement Factor B↗
PubMed1991

Population genetics in forensic DNA typing.

Variable number of tandem repeat (VNTR) sequences are used to link defendants with crimes by matching DNA patterns. The probative value of a match is often calculated by multiplying together the estimated frequencies with which each particular VNTR pattern occurs in a reference database. However, this method is liable to potentially serious errors because ethnic subgroups within major racial categories exhibit genetic differences that are maintained by endogamy. The multiplication procedure currently in use can be made scientifically valid only by extensive sampling of VNTR frequency distributions in a variety of ethnic groups, similar to the ethnic studies of various blood groups done in the past. Alternative approaches for dealing with subpopulation heterogeneity are discussed.

Alleles↗
PubMed2002

Archived or directly swabbed latent fingerprints as a DNA source for STR typing.

Former studies [Nature (1997) 387, Electrophoresis 20 (1999) 2870, P. Van Renterghem, D. Leonard, C. De Greef, Progress in Forensic Genetics, Vol. 8, 2000, p. 501, J. Forensic Sci. 45 (3) (2000) 687] have shown that even a single skin contact, documented by a latent fingerprint, can transfer enough DNA for a genetic analysis. It was proven in these studies that it is possible to swab fingerprints from surfaces [Nature (1997) 387, Electrophoresis 20 (1999) 2870, P. Van Renterghem, D. Leonard, C. De Greef, Progress in Forensic Genetics, Vol. 8, 2000, p. 501] and use them as a DNA source. Usually, however, discovered fingerprints are removed with scotch tape and placed on evidence cards for further investigation.In this study, we tried to assess the potential use of latent fingerprints as a DNA source for STR typing. The materials (magnetic powder, soot powder and scotch tape) used for visualization and archiving fingerprints in Germany were tested for their PCR inhibitory characteristics. Then, fingerprints were placed on clean glass surfaces, visualized and tested for their usefulness as a DNA source. Obtained DNA was quantified and tested in an STR system. Partly it proved possible to type fingerprints taken directly from the surface as well as fingerprints removed from the surface with scotch tape.

DNA Fingerprinting↗
PubMed2003

Genetics and Forensics: Making the National DNA Database.

This paper is based on a current study of the growing police use of the epistemic authority of molecular biology for the identification of criminal suspects in support of crime investigation. It discusses the development of DNA profiling and the establishment and development of the UK National DNA Database (NDNAD) as an instance of the 'scientification of police work' (Ericson and Shearing 1986) in which the police uses of science and technology have a recursive effect on their future development. The NDNAD, owned by the Association of Chief Police Officers of England and Wales, is the first of its kind in the world and currently contains the genetic profiles of more than 2 million people. The paper provides a framework for the examination of this socio-technical innovation, begins to tease out the dense and compact history of the database and accounts for the way in which changes and developments across disparate scientific, governmental and policing contexts, have all contributed to the range of uses to which it is put.

Journal Article↗
PubMed1992

Population genetics and forensic efficiency data of 4 AMPFLP's.

Family studies were carried out in a population sample from north west Germany using 4 amplifiable VNTR polymorphic systems D1S80 (MCT118), ApoB, D17S30 (YNZ22) and COL2A1. Separation was carried out in polyacrylamide gels and visualised using silver staining. In family studies (n = 30) no evidence of new mutations was found. The population study of unrelated individuals (mothers and putative fathers) showed that all 4 systems were highly polymorphic and similar to other population studies. The combined exclusion chance was calculated to be approximately 99% and the combined discrimination index 1.5.10(-4). The Hardy-Weinberg equilibrium was checked by forming groups of alleles and no significant deviations could be found in all systems.

Alleles↗
PubMed2002

Sequence structure and population data of two X-linked markers: DXS7423 and DXS8377.

DXS7423 and DXS8377 are two microsatellite markers located in the q28 band of chromosome X. We developed a protocol to amplify both markers in a single reaction, sequenced the most common alleles and studied allele frequencies in a Spanish population sample. DXS7423 allele variability was due to different numbers of (TCCA) repeats and five different alleles were found with apparent sizes between 181 and 197 bp. The probability of discrimination (PD) was 87% for female samples, and the expected probability of exclusion (PE) was 71%. DXS8377 appeared as a highly polymorphic marker with variable numbers of (CTC), (TCC) and (TTC) repeats. We found 18 alleles of different sizes (204-258 bp) and the PD and PE were 99% and 93%, respectively. These data suggest that DXS7423 and DXS8377 can be very useful markers for genetic forensic studies.

Chromosomes, Human, X↗
PubMed1990

The technique of polymerase chain reaction--a new diagnostic tool in microbiology and other scientific fields (review).

The polymerase chain reaction, a method of so far unknown sensitivity and specificity, is about to become an important diagnostic tool in microbiology. Practically even a single bacterium, virus particle, or parasite can be detected by it. Furthermore, this technique has been used with highly promising results in other scientific fields like genetics, forensic medicine and archeology. This article reviews technical aspects and variations of this new technique.

Animals↗